hw/pcspk.c

   1 /*
   2  * QEMU PC speaker emulation
   3  *
   4  * Copyright (c) 2006 Joachim Henke
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24
  25 #include "hw.h"
  26 #include "pc.h"
  27 #include "isa.h"
  28 #include "audio/audio.h"
  29 #include "qemu-timer.h"
  30 #include "i8254.h"
  31 #include "qemu-kvm.h"
  32
  33 #define PCSPK_BUF_LEN 1792
  34 #define PCSPK_SAMPLE_RATE 32000
  35 #define PCSPK_MAX_FREQ (PCSPK_SAMPLE_RATE >> 1)
  36 #define PCSPK_MIN_COUNT ((PIT_FREQ + PCSPK_MAX_FREQ - 1) / PCSPK_MAX_FREQ)
  37
  38 typedef struct {
  39     uint8_t sample_buf[PCSPK_BUF_LEN];
  40     QEMUSoundCard card;
  41     SWVoiceOut *voice;
  42     PITState *pit;
  43     unsigned int pit_count;
  44     unsigned int samples;
  45     unsigned int play_pos;
  46     int data_on;
  47     int dummy_refresh_clock;
  48 } PCSpkState;
  49
  50 static const char *s_spk = "pcspk";
  51 static PCSpkState pcspk_state;
  52
  53 #ifdef USE_KVM_PIT
  54 static void kvm_get_pit_ch2(PITState *pit,
  55                             struct kvm_pit_state *inkernel_state)
  56 {
  57     struct kvm_pit_state pit_state;
  58
  59     if (kvm_enabled() && qemu_kvm_pit_in_kernel()) {
  60         kvm_get_pit(kvm_context, &pit_state);
  61         pit->channels[2].mode = pit_state.channels[2].mode;
  62         pit->channels[2].count = pit_state.channels[2].count;
  63         pit->channels[2].count_load_time = pit_state.channels[2].count_load_time;
  64         pit->channels[2].gate = pit_state.channels[2].gate;
  65         if (inkernel_state) {
  66             memcpy(inkernel_state, &pit_state, sizeof(*inkernel_state));
  67         }
  68     }
  69 }
  70
  71 static void kvm_set_pit_ch2(PITState *pit,
  72                             struct kvm_pit_state *inkernel_state)
  73 {
  74     if (kvm_enabled() && qemu_kvm_pit_in_kernel()) {
  75         inkernel_state->channels[2].mode = pit->channels[2].mode;
  76         inkernel_state->channels[2].count = pit->channels[2].count;
  77         inkernel_state->channels[2].count_load_time =
  78             pit->channels[2].count_load_time;
  79         inkernel_state->channels[2].gate = pit->channels[2].gate;
  80         kvm_set_pit(kvm_context, inkernel_state);
  81     }
  82 }
  83 #else
  84 static inline void kvm_get_pit_ch2(PITState *pit,
  85                                    struct kvm_pit_state *inkernel_state) { }
  86 static inline void kvm_set_pit_ch2(PITState *pit,
  87                                    struct kvm_pit_state *inkernel_state) { }
  88 #endif
  89
  90 static inline void generate_samples(PCSpkState *s)
  91 {
  92     unsigned int i;
  93
  94     if (s->pit_count) {
  95         const uint32_t m = PCSPK_SAMPLE_RATE * s->pit_count;
  96         const uint32_t n = ((uint64_t)PIT_FREQ << 32) / m;
  97
  98         /* multiple of wavelength for gapless looping */
  99         s->samples = (PCSPK_BUF_LEN * PIT_FREQ / m * m / (PIT_FREQ >> 1) + 1) >> 1;
 100         for (i = 0; i < s->samples; ++i)
 101             s->sample_buf[i] = (64 & (n * i >> 25)) - 32;
 102     } else {
 103         s->samples = PCSPK_BUF_LEN;
 104         for (i = 0; i < PCSPK_BUF_LEN; ++i)
 105             s->sample_buf[i] = 128; /* silence */
 106     }
 107 }
 108
 109 static void pcspk_callback(void *opaque, int free)
 110 {
 111     PCSpkState *s = opaque;
 112     unsigned int n;
 113
 114     kvm_get_pit_ch2(s->pit, NULL);
 115
 116     if (pit_get_mode(s->pit, 2) != 3)
 117         return;
 118
 119     n = pit_get_initial_count(s->pit, 2);
 120     /* avoid frequencies that are not reproducible with sample rate */
 121     if (n < PCSPK_MIN_COUNT)
 122         n = 0;
 123
 124     if (s->pit_count != n) {
 125         s->pit_count = n;
 126         s->play_pos = 0;
 127         generate_samples(s);
 128     }
 129
 130     while (free > 0) {
 131         n = audio_MIN(s->samples - s->play_pos, (unsigned int)free);
 132         n = AUD_write(s->voice, &s->sample_buf[s->play_pos], n);
 133         if (!n)
 134             break;
 135         s->play_pos = (s->play_pos + n) % s->samples;
 136         free -= n;
 137     }
 138 }
 139
 140 int pcspk_audio_init(qemu_irq *pic)
 141 {
 142     PCSpkState *s = &pcspk_state;
 143     struct audsettings as = {PCSPK_SAMPLE_RATE, 1, AUD_FMT_U8, 0};
 144
 145     AUD_register_card(s_spk, &s->card);
 146
 147     s->voice = AUD_open_out(&s->card, s->voice, s_spk, s, pcspk_callback, &as);
 148     if (!s->voice) {
 149         AUD_log(s_spk, "Could not open voice\n");
 150         return -1;
 151     }
 152
 153     return 0;
 154 }
 155
 156 static uint32_t pcspk_ioport_read(void *opaque, uint32_t addr)
 157 {
 158     PCSpkState *s = opaque;
 159     int out;
 160
 161     kvm_get_pit_ch2(s->pit, NULL);
 162
 163     s->dummy_refresh_clock ^= (1 << 4);
 164     out = pit_get_out(s->pit, 2, qemu_get_clock(vm_clock)) << 5;
 165
 166     return pit_get_gate(s->pit, 2) | (s->data_on << 1) | s->dummy_refresh_clock | out;
 167 }
 168
 169 static void pcspk_ioport_write(void *opaque, uint32_t addr, uint32_t val)
 170 {
 171     struct kvm_pit_state inkernel_state;
 172     PCSpkState *s = opaque;
 173     const int gate = val & 1;
 174
 175     kvm_get_pit_ch2(s->pit, &inkernel_state);
 176
 177     s->data_on = (val >> 1) & 1;
 178     pit_set_gate(s->pit, 2, gate);
 179     if (s->voice) {
 180         if (gate) /* restart */
 181             s->play_pos = 0;
 182         AUD_set_active_out(s->voice, gate & s->data_on);
 183     }
 184
 185     kvm_set_pit_ch2(s->pit, &inkernel_state);
 186 }
 187
 188 void pcspk_init(PITState *pit)
 189 {
 190     PCSpkState *s = &pcspk_state;
 191
 192     s->pit = pit;
 193     register_ioport_read(0x61, 1, 1, pcspk_ioport_read, s);
 194     register_ioport_write(0x61, 1, 1, pcspk_ioport_write, s);
 195 }